To utilize the characteristics of liquid crystal panels that they are reduced in thickness, size, weight and power consumption, liquid crystal television receivers and liquid crystal projectors incorporating a liquid crystal panel have been developed.
Original images are formed on liquid crystal panels by a multiplicity of picture elements (pixels), so that no problem is encountered in directly viewing liquid crystal television receivers, whereas liquid crystal projectors have the following two problems since in this case, light from a light source is passed through the liquid crystal panel to project the image thereon onto a screen upon enlargement.
The first of the problems is that especially with liquid crystal projectors having three liquid crystal panels for red, green and blue colors, the source lines and gate lines extending from the respective liquid crystal cells forming the panels are projected as enlarged, producing lattice shade on the screen to lower the quality of images.
The second problem is that especially with liquid crystal projectors having a single liquid crystal panel and a single color filter for the three primary colors, the red picture elements, green picture elements and blue picture elements forming images are individually projected as enlarged on a screen, such that the picture elements of three primary colors in a set are arranged with a large pitch to produce images of impaired quality.
To solve these problems, Unexamined Japanese Patent Publication SHO 63-292880 discloses a liquid crystal projector wherein the original image formed on a liquid crystal panel is projected as enlarged onto a screen by passing light from a light source through the panel, and which includes an optical axis vibrating device interposed between the liquid crystal panel and the screen for vibrating the image to be projected onto the screen with a predetermined cycle.
However, the liquid crystal projector is complex in construction and large-sized since the projector additionally requires the optical axis vibrating device. Furthermore, it is difficult to accurately control the amplitude of vibration of images by the vibrating device, which is therefore likely to undesirably lower the resolution of images to be projected.